绿海龟稚龟高密度养殖越冬技术初报

多年的研究数据表明,每年9月份后出壳的稚龟个体较小,在12月前平均体重少于70 g,占死亡总数的90%以上.原因是稚龟冬季的摄食能力下降,个体较小的稚龟体质差,没有足够的能量御寒.而采用加温和药物预防措施效果不佳.2004年,我们采取绿海龟高密度养殖方法,按照绿海龟的自然生活习性,从改善水质和食物,增强稚龟体质入手,使其越冬前体重迅速增加到100 g以上,御寒能力增强,可有效保证稚龟顺利过冬,成活率可达90%以上.     

稚绿海龟Chelonia mydas白化个体及畸形卵的观察

2001年, 广东惠东港口海龟国家级自然保护区管理局在 1000 多枚绿海龟的卵孵化过程中, 发现一例白化稚绿海龟 (见封3图版, 1)。现报道如下。白化稚绿海龟通体白色; 背甲、腹甲和四肢发育正常, 其量度见表 1。背甲卵圆形, 中央隆起,椎盾5枚, 肋盾8枚, 颈盾2枚, 左侧缘盾12枚,表1　白化稚绿海龟 (编重量体长背甲长背甲宽腹甲长腹甲宽15 2 53 38 40 9 35 3 25 01 23 36 　　人类白化病患者眼睛呈肉红色[1]。白化龟、白化鳖眼睛曾出现红色和黑色两种现象。该稚绿海龟白化个体因无眼睛, 故不知其…     

绿海龟稚龟性别鉴定及临界温度

通过组织形态学鉴定、羊水和血液中性激素测定等手段,对惠东港口海龟保护区不同恒温下孵化的绿海龟(Chelonia mydas)进行研究,寻求绿海龟稚龟性别鉴定的最佳方法。结果显示,(1)组织形态学,绿海龟性腺切片分皮层和髓质两部分,卵巢的皮层较厚、基质中有大小不一的未成熟卵细胞,髓质中空腔较少;睾丸的皮层较薄,髓质中空腔较多,呈现出显著的被基质包围的髓质索。(2)性激素测定,当雌二醇与睾酮含量之比E2∶T1.5时,孵出的稚龟为雄性(♂);当E2∶T1.5时,为雌性(♀)。(3)绿海龟性别决定的临界温度在29.4～29.5℃之间,此时孵出稚龟的性比约为1∶1。本文还讨论了各种不同性别鉴定方法的优劣和时期选择。     

中国海龟的保护问题

在中国,共有5种海龟会在东侧的大陆棚沿岸海域及南中国海出现,它们分别是绿海龟（Cheloniamyds）,龟（Carettacaretta）,玳瑁（Eretmochelysimbricata）,丽龟（Lepidochelysolivacea）,及棱皮龟（Dermochelyscoriacea）。在这5种海龟中,以绿海龟的数量为最多。此外在5种海龟中,仅有绿海龟、龟及玳瑁会在我国领土沿海的沙滩上产卵。和其他的沿海民族一样,数千年来,沿海省份的居民,不但捕食海龟及龟蛋,而且利用其部分的身体做为中药材来治疗高血压等疾病,或将其皮甲制成标本出售,稚龟亦被当成水族宠物加以出售图利。根据估计…     

不同年龄绿海龟口腔的组织形态及超微结构比较

对不同年龄段绿海龟Chelonia mydas的口腔进行形态学观察。口腔均由喙、内鼻孔、舌、气门及咽喉腔组成。喙覆盖角质鞘,无牙齿。稚龟喙呈V型,无角质锯齿,下喙钩状;幼龟和成年龟喙呈U型,具多排角质锯齿,口裂均相对较稚龟小。上喙内侧角化内鼻孔2个;内鼻孔梳状乳突在稚龟中缺失,但在幼龟和成年龟中可见,且随年龄增长、增密。舌呈"U"型,短小;舌正后方有游离的半圆形膜状皱褶,其下方可见1个裂隙。气门紧随裂隙内侧,游离,由2个杓状软骨支撑。舌和气门下方舌骨1块;角腮骨1对,分别可伸至咽喉腔下方和头骨后方。咽喉腔约占口腔的1/2,表层分布有大量弧状皱褶,且左右各具1个咽鼓管孔。光镜下,口腔腔壁包含黏膜层、肌层和骨骼。黏膜层均由角化复层鳞状上皮和固有层构成,但仅稚龟舌后部的黏膜层可见分泌细胞分布。舌体与膜状皱褶之间有分支泡状腺;膜状皱褶下方的裂隙表面覆盖复层柱状上皮,可见管状腺分布;复层柱状上皮细胞和腺体细胞在ABPAS染色中均呈玫红色。肌层为骨骼肌,其在舌体分布较少,而在气门区域较发达。扫描电镜下,口腔黏膜上皮由多边形的角质细胞组成,其表面有不规则的波纹分布,微绒毛和杯状细胞均缺失。绿海龟口腔的组织形态及结构与其食性及生态适应紧密相关。     

海龟漫谈

海龟是对生活在海洋里的各种龟类的总称，它们广泛地分布于全球各地温暖的海域里。全世界现存的海龟共有7种，我国有5种，分别是：海龟（也叫绿海龟），蠵（xi）龟、玳瑁、丽龟（也叫太平洋丽龟）和棱皮龟。     

黄喉拟水龟的繁殖生物学研究

1998年4-11月对黄喉拟水龟的繁殖生物学进行了研究,在广东,黄喉拟水龟的产卵高峰期在5-6月,窝卵量1-7枚,平均2.5枚;卵重平均13.95g;长径平均4.34cm;短径平均2.23cm。卵重与卵长径呈正相关关系,在25-32℃、沙床含水量5-10%孵化条件下,孵化时间平衡73.8d,孵化率84.2%。初生稚龟均重9.75g。背甲长平均3.77cm;背甲宽平均2.91cm。稚龟体重与背甲长、宽呈极显著的正相关关系,稚龟经8-11月3个月生长,平均日增重0.149g。稚龟体重、背甲长、宽与日龄呈极显著的正相关关系。稚龟体重与背甲长宽也呈极显著的正相关关系。     

乌龟Chinemys reevesii胚胎发育的初步观察

乌龟产下来的受精卵是在母体内经历了卵裂、囊胚等发育阶段的。在其以后的胚胎发育过程中形成中胚层囊、卵黄囊血管区、羊膜和浆膜。较晚阶段的胚胎更有尿囊伸到浆、羊膜腔中,几乎包围了整个胚胎和卵黄囊、受精卵在人工设置的温床中,相对湿度80—84％,温度33±1℃—35±1℃,均可孵出稚龟。适宜孵化温度33±1℃,历时45—48天,比自然界提早出壳时间20—25天,这对提高孵化率、延长当龄稚龟的生长期和提高稚龟的成活率均有重要意义。     

稚海龟的雌雄辨别

稚海龟的雌雄辨别张晓荣，李放明，王伦武（广东港口海龟自然保护区管理站广东５１６３５９）海龟（Ｃｈｅｌｏｎｉａｍｙｄａｓｊａｐｏｎｉｃａ），俗称绿海龟（Ｇｒｅｅｎｔｕｒｔｌｅ），象其它亚种：Ｃ．ｍｙｄａｓｍｙａｓ，Ｃ．ｍｙｄａｓａｇａｓｉｊｚｊｊＣ．ｍ...     

绿海龟背甲盾片的变异

通过对 2 92只 1龄绿海龟活体和 114只当年龟标本观察 ,发现 6 0只龟背甲盾片有变异现象。变异部位表现在椎盾、肋盾 ,颈盾和缘盾 ,未发现臀盾变异现象。各部位变异频率依次为椎盾 >椎盾和肋盾同时变异>多个部位同时变异 >肋盾 >颈盾 >缘盾。测量正常龟和变异龟各 15只的背甲长、宽和高 ,经t值检验 ,差异均不显著 ,说明正常龟和变异龟的背甲形状无明显差别 ,盾片数目的变化属个体变异。     

Fibropapillomatosis and the Chelonid Alphaherpesvirus 5 in Green Turtles from West Africa

EcoHealth - Fibropapillomatosis (FP) is a tumorigenic panzootic disease of sea turtles, most common in green turtles (Chelonia mydas). FP is linked to the chelonid alphaherpesvirus 5 (ChAHV5) and...     

Fish assemblage structure response to seagrass bed degradation due to overgrazing by the green sea turtle Chelonia mydas at Iriomote Island,southern Japan

Ichthyological Research - The fish assemblage structure response to rapid degradation of Enhalus acoroides seagrass beds due to overgrazing by green sea turtles (Chelonia mydas) was investigated at...     

Long-term satellite telemetry of the movements and habitat utilisation by green turtles in the Mediterranean

There is a relative paucity of data regarding the at-sea distribution and behaviour of marine turtles. This is especially true for the critically endangered green turtle Chelonia mydas population in the Mediterranean. Six adult female green turtles were equipped with satellite transmitters and tracked for periods of between 28 and 293 d following their final nesting of the season in northern Cyprus. Data elucidated hitherto unknown migratory pathways and highlighted the importance of North African coastal waters as feeding habitat for adults of this species. For three individuals, instruments transmitted detailed information on dive depth, dive duration and water temperature which afforded novel insights into behaviour during different stages of migration, feeding in the foraging grounds and most remarkably, during a period of midwinter diapause when water temperatures were generally below 25°C. Turtles showed fidelity to specific shallow inshore feeding areas and moved offshore to deeper wintering sites.     

Trophic status drives interannual variability in nesting numbers of marine turtles.

Large annual fluctuations are seen in breeding numbers in many populations of non-annual breeders. We examined the interannual variation in nesting numbers of populations of green (Chelonia mydas) (n = 16 populations), loggerhead (Caretta caretta) (n = 10 populations), leatherback (Dermochelys coriacea) (n = 9 populations) and hawksbill turtles (Eretmochelys imbricata) (n = 10 populations). Interannual variation was greatest in the green turtle. When comparing green and loggerhead turtles nesting in Cyprus we found that green turtles were more likely to change the interval between laying seasons and showed greater variation in the number of clutches laid in a season. We suggest that these differences are driven by the varying trophic statuses of the different species. Green turtles are herbivorous, feeding on sea grasses and macro-algae, and this primary production will be more tightly coupled with prevailing environmental conditions than the carnivorous diet of the loggerhead turtle.     

Cryptosporidium sp. Infections in Green Turtles, Chelonia mydas, as a Potential Source of Marine Waterborne Oocysts in the Hawaiian Islands

For the first time, Cryptosporidium sp. oocysts were identified in fecal and intestinal samples from free-ranging marine turtles, Chelonia mydas, from the Hawaiian Islands. The oocysts produced positive reactions with commercial test kits recommended for the detection of human-infectious waterborne oocysts of Cryptosporidium parvum.     

Island-finding ability of marine turtles

Green turtles (Chelonia mydas) swim from foraging grounds along the Brazilian coast to Ascension Island to nest, over 2200 km distant in the middle of the equatorial Atlantic. To test the hypothesis that turtles use wind-borne cues to locate Ascension Island we found turtles that had just completed nesting and then moved three individuals 50 km northwest (downwind) of the island and three individuals 50 km southeast (upwind). Their subsequent movements were tracked by satellite. Turtles released downwind returned to Ascension Island within 1, 2 and 4 days, respectively. By contrast, those released upwind had far more difficulty in relocating Ascension Island, two eventually returning after 10 and 27 days and the third heading back to Brazil after failing to find its way back to the island. These findings strongly support the hypothesis that wind-borne cues are used by turtles to locate Ascension Island.     

Blood profiles for a wild population of green turtles (Chelonia mydas) in the southern Bahamas: size-specific and sex-specific relationships.

Blood biochemical profiles and packed cell volumes were determined for 100 juvenile green turtles, Chelonia mydas, from a wild population in the southern Bahamas. There was a significant correlation of body size to 13 of the 26 blood parameters measured. Only plasma uric acid and cholesterol were significantly different between male and female turtles. The relationship between total plasma proteins and plasma refractive index was significant. The equation for converting refractive index (Y) to total plasma proteins (X) is Y = 1.34 + 0.00217(X).     

Nocturnal activity in the green sea turtle alters daily profiles of melatonin and corticosterone

In nature, green turtles (Chelonia mydas) can exhibit nocturnal activity in addition to their typically diurnal activity cycle. We examined whether nocturnal activity in captive and free-living green turtles altered daily plasma profiles of melatonin (MEL) and corticosterone (CORT). In captivity, diurnally active green turtles expressed distinct diel cycles in MEL and CORT; a nocturnal rise was observed in MEL and a diurnal rise was observed in CORT. However, when induced to perform both low- and high-intensity nocturnal activity, captive green turtles exhibited a significant decrease in MEL, compared to inactive controls. In contrast, plasma CORT increased significantly with nocturnal activity, and further, the relative increase in CORT was correlated with the intensity of the nocturnal behavior. In free-living green turtles that performed nocturnal activity including: nesting, mate searching, and feeding/swimming behaviors, plasma profiles in MEL and CORT exhibited relatively little, or no, daily fluctuation. Our findings demonstrate that nocturnal activity in green turtles is often associated with MEL and CORT profiles that resemble those measured during the day. We speculate that these conspicuous changes in MEL and CORT during nocturnal activity could either support or promote behaviors that enable acquisition of transient resources important to the survival and reproductive success of green turtles.     

Genetic structure and diversity of green sea turtle (Chelonia mydas) from South China Sea inferred by mtDNA control region sequence

We analyzed 88 control region sequences of green sea turtle (Chelonia mydas) from around Hainan Island in the South China Sea. These sequences had a length of 489 bp and revealed 8 mtDNA haplotypes of which four haplotypes (CMC1, CMC4, CMC7, and CMC8) had not been discovered before. Haplotype diversity (h) and nucleotide diversity (π) were 0.45 ± 0.054 and 0.0035 ± 0.0014, respectively. Neighbor-Joining tree based on control region sequences revealed that genetic relationship between green sea turtles from the South China Sea and from Japan Sea were very close. Clustering relationship based on control region sequences indicated that the South China Sea is an important breeding site and feeding habitat for green sea turtles, which connects with the Middle East Pacific, the Southwest Pacific and the Indian Ocean.